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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
.text
.global memset
.type memset, %function
.global bzero
.type bzero, %function
.align
/*
* Optimized memset() for ARM.
*
* memset() returns its first argument.
*/
bzero:
mov r2, r1
mov r1, #0
memset:
/* compute the offset to align the destination
* offset = (4-(src&3))&3 = -src & 3
*/
.fnstart
.save {r0, r4-r7, lr}
stmfd sp!, {r0, r4-r7, lr}
rsb r3, r0, #0
ands r3, r3, #3
cmp r3, r2
movhi r3, r2
/* splat r1 */
mov r1, r1, lsl #24
orr r1, r1, r1, lsr #8
orr r1, r1, r1, lsr #16
movs r12, r3, lsl #31
strcsb r1, [r0], #1 /* can't use strh (alignment unknown) */
strcsb r1, [r0], #1
strmib r1, [r0], #1
subs r2, r2, r3
ldmlsfd sp!, {r0, r4-r7, lr} /* return */
bxls lr
/* align the destination to a cache-line */
mov r12, r1
mov lr, r1
mov r4, r1
mov r5, r1
mov r6, r1
mov r7, r1
rsb r3, r0, #0
ands r3, r3, #0x1C
beq 3f
cmp r3, r2
andhi r3, r2, #0x1C
sub r2, r2, r3
/* conditionnaly writes 0 to 7 words (length in r3) */
movs r3, r3, lsl #28
stmcsia r0!, {r1, lr}
stmcsia r0!, {r1, lr}
stmmiia r0!, {r1, lr}
movs r3, r3, lsl #2
strcs r1, [r0], #4
3:
subs r2, r2, #32
mov r3, r1
bmi 2f
1: subs r2, r2, #32
stmia r0!, {r1,r3,r4,r5,r6,r7,r12,lr}
bhs 1b
2: add r2, r2, #32
/* conditionnaly stores 0 to 31 bytes */
movs r2, r2, lsl #28
stmcsia r0!, {r1,r3,r12,lr}
stmmiia r0!, {r1, lr}
movs r2, r2, lsl #2
strcs r1, [r0], #4
strmih r1, [r0], #2
movs r2, r2, lsl #2
strcsb r1, [r0]
ldmfd sp!, {r0, r4-r7, lr}
bx lr
.fnend
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